Every device being hackable
The holy grail of cryptography is not that you can't access the encrypted data, but that you don't know if you have.
Crypto, typically, makes semirandom changes to the data until it looks like what it's supposed to. It is also possible that making the wrong kind of semirandom changes to the encrypted data will result in you seeing Goatse instead of a vulnerable person's private emails. If the eavesdropper doesn't know whether the vulnerable person is emailing Goatse then they cannot know whether there is anything to continue trying to decrypt.
Biting the hand that feeds IT
